Change line manager of a department

Summary

change line manager of all employees of a department

Content

Hi all,

We are trying to update the information of some employees, temporarily.
The problem that is happenning is when i update the position of someone to manager. It gets the correct job and department but the line manager is kept static.
How can I assign this new line manager for all employees of such department at once?

I tried going into configuration of positions but the line manager can be set by name when I need it to be assigned to a specific position.

Thank you all